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82da3ff8 IM |
1 | /* |
2 | * This program is free software; you can redistribute it and/or modify it | |
3 | * under the terms of the GNU General Public License as published by the | |
4 | * Free Software Foundation; either version 2, or (at your option) any | |
5 | * later version. | |
6 | * | |
7 | * This program is distributed in the hope that it will be useful, but | |
8 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
10 | * General Public License for more details. | |
11 | * | |
12 | */ | |
13 | ||
14 | /* | |
15 | * Copyright (C) 2004 Amit S. Kale <amitkale@linsyssoft.com> | |
16 | * Copyright (C) 2000-2001 VERITAS Software Corporation. | |
17 | * Copyright (C) 2002 Andi Kleen, SuSE Labs | |
18 | * Copyright (C) 2004 LinSysSoft Technologies Pvt. Ltd. | |
19 | * Copyright (C) 2007 MontaVista Software, Inc. | |
20 | * Copyright (C) 2007-2008 Jason Wessel, Wind River Systems, Inc. | |
21 | */ | |
22 | /**************************************************************************** | |
23 | * Contributor: Lake Stevens Instrument Division$ | |
24 | * Written by: Glenn Engel $ | |
25 | * Updated by: Amit Kale<akale@veritas.com> | |
26 | * Updated by: Tom Rini <trini@kernel.crashing.org> | |
27 | * Updated by: Jason Wessel <jason.wessel@windriver.com> | |
28 | * Modified for 386 by Jim Kingdon, Cygnus Support. | |
29 | * Origianl kgdb, compatibility with 2.1.xx kernel by | |
30 | * David Grothe <dave@gcom.com> | |
31 | * Integrated into 2.2.5 kernel by Tigran Aivazian <tigran@sco.com> | |
32 | * X86_64 changes from Andi Kleen's patch merged by Jim Houston | |
33 | */ | |
34 | #include <linux/spinlock.h> | |
35 | #include <linux/kdebug.h> | |
36 | #include <linux/string.h> | |
37 | #include <linux/kernel.h> | |
38 | #include <linux/ptrace.h> | |
39 | #include <linux/sched.h> | |
40 | #include <linux/delay.h> | |
41 | #include <linux/kgdb.h> | |
42 | #include <linux/init.h> | |
43 | #include <linux/smp.h> | |
d3597524 | 44 | #include <linux/nmi.h> |
cc096749 | 45 | #include <linux/hw_breakpoint.h> |
82da3ff8 | 46 | |
62edab90 | 47 | #include <asm/debugreg.h> |
82da3ff8 IM |
48 | #include <asm/apicdef.h> |
49 | #include <asm/system.h> | |
7b6aa335 | 50 | #include <asm/apic.h> |
82da3ff8 | 51 | |
12bfa3de | 52 | struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = |
82da3ff8 | 53 | { |
12bfa3de JW |
54 | #ifdef CONFIG_X86_32 |
55 | { "ax", 4, offsetof(struct pt_regs, ax) }, | |
56 | { "cx", 4, offsetof(struct pt_regs, cx) }, | |
57 | { "dx", 4, offsetof(struct pt_regs, dx) }, | |
58 | { "bx", 4, offsetof(struct pt_regs, bx) }, | |
59 | { "sp", 4, offsetof(struct pt_regs, sp) }, | |
60 | { "bp", 4, offsetof(struct pt_regs, bp) }, | |
61 | { "si", 4, offsetof(struct pt_regs, si) }, | |
62 | { "di", 4, offsetof(struct pt_regs, di) }, | |
63 | { "ip", 4, offsetof(struct pt_regs, ip) }, | |
64 | { "flags", 4, offsetof(struct pt_regs, flags) }, | |
65 | { "cs", 4, offsetof(struct pt_regs, cs) }, | |
66 | { "ss", 4, offsetof(struct pt_regs, ss) }, | |
67 | { "ds", 4, offsetof(struct pt_regs, ds) }, | |
68 | { "es", 4, offsetof(struct pt_regs, es) }, | |
69 | { "fs", 4, -1 }, | |
70 | { "gs", 4, -1 }, | |
71 | #else | |
72 | { "ax", 8, offsetof(struct pt_regs, ax) }, | |
73 | { "bx", 8, offsetof(struct pt_regs, bx) }, | |
74 | { "cx", 8, offsetof(struct pt_regs, cx) }, | |
75 | { "dx", 8, offsetof(struct pt_regs, dx) }, | |
76 | { "si", 8, offsetof(struct pt_regs, dx) }, | |
77 | { "di", 8, offsetof(struct pt_regs, di) }, | |
78 | { "bp", 8, offsetof(struct pt_regs, bp) }, | |
79 | { "sp", 8, offsetof(struct pt_regs, sp) }, | |
80 | { "r8", 8, offsetof(struct pt_regs, r8) }, | |
81 | { "r9", 8, offsetof(struct pt_regs, r9) }, | |
82 | { "r10", 8, offsetof(struct pt_regs, r10) }, | |
83 | { "r11", 8, offsetof(struct pt_regs, r11) }, | |
84 | { "r12", 8, offsetof(struct pt_regs, r12) }, | |
85 | { "r13", 8, offsetof(struct pt_regs, r13) }, | |
86 | { "r14", 8, offsetof(struct pt_regs, r14) }, | |
87 | { "r15", 8, offsetof(struct pt_regs, r15) }, | |
88 | { "ip", 8, offsetof(struct pt_regs, ip) }, | |
89 | { "flags", 4, offsetof(struct pt_regs, flags) }, | |
90 | { "cs", 4, offsetof(struct pt_regs, cs) }, | |
91 | { "ss", 4, offsetof(struct pt_regs, ss) }, | |
703a1edc | 92 | #endif |
12bfa3de JW |
93 | }; |
94 | ||
95 | int dbg_set_reg(int regno, void *mem, struct pt_regs *regs) | |
96 | { | |
97 | if ( | |
82da3ff8 | 98 | #ifdef CONFIG_X86_32 |
12bfa3de JW |
99 | regno == GDB_SS || regno == GDB_FS || regno == GDB_GS || |
100 | #endif | |
101 | regno == GDB_SP || regno == GDB_ORIG_AX) | |
102 | return 0; | |
103 | ||
104 | if (dbg_reg_def[regno].offset != -1) | |
105 | memcpy((void *)regs + dbg_reg_def[regno].offset, mem, | |
106 | dbg_reg_def[regno].size); | |
107 | return 0; | |
108 | } | |
109 | ||
110 | char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs) | |
111 | { | |
112 | if (regno == GDB_ORIG_AX) { | |
113 | memcpy(mem, ®s->orig_ax, sizeof(regs->orig_ax)); | |
114 | return "orig_ax"; | |
cf6f196d | 115 | } |
12bfa3de JW |
116 | if (regno >= DBG_MAX_REG_NUM || regno < 0) |
117 | return NULL; | |
118 | ||
119 | if (dbg_reg_def[regno].offset != -1) | |
120 | memcpy(mem, (void *)regs + dbg_reg_def[regno].offset, | |
121 | dbg_reg_def[regno].size); | |
122 | ||
123 | switch (regno) { | |
124 | #ifdef CONFIG_X86_32 | |
125 | case GDB_SS: | |
126 | if (!user_mode_vm(regs)) | |
127 | *(unsigned long *)mem = __KERNEL_DS; | |
128 | break; | |
129 | case GDB_SP: | |
130 | if (!user_mode_vm(regs)) | |
131 | *(unsigned long *)mem = kernel_stack_pointer(regs); | |
132 | break; | |
133 | case GDB_GS: | |
134 | case GDB_FS: | |
135 | *(unsigned long *)mem = 0xFFFF; | |
136 | break; | |
cf6f196d | 137 | #endif |
12bfa3de JW |
138 | } |
139 | return dbg_reg_def[regno].name; | |
82da3ff8 IM |
140 | } |
141 | ||
142 | /** | |
143 | * sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs | |
144 | * @gdb_regs: A pointer to hold the registers in the order GDB wants. | |
145 | * @p: The &struct task_struct of the desired process. | |
146 | * | |
147 | * Convert the register values of the sleeping process in @p to | |
148 | * the format that GDB expects. | |
149 | * This function is called when kgdb does not have access to the | |
150 | * &struct pt_regs and therefore it should fill the gdb registers | |
151 | * @gdb_regs with what has been saved in &struct thread_struct | |
152 | * thread field during switch_to. | |
153 | */ | |
154 | void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) | |
155 | { | |
703a1edc JW |
156 | #ifndef CONFIG_X86_32 |
157 | u32 *gdb_regs32 = (u32 *)gdb_regs; | |
158 | #endif | |
82da3ff8 IM |
159 | gdb_regs[GDB_AX] = 0; |
160 | gdb_regs[GDB_BX] = 0; | |
161 | gdb_regs[GDB_CX] = 0; | |
162 | gdb_regs[GDB_DX] = 0; | |
163 | gdb_regs[GDB_SI] = 0; | |
164 | gdb_regs[GDB_DI] = 0; | |
165 | gdb_regs[GDB_BP] = *(unsigned long *)p->thread.sp; | |
166 | #ifdef CONFIG_X86_32 | |
167 | gdb_regs[GDB_DS] = __KERNEL_DS; | |
168 | gdb_regs[GDB_ES] = __KERNEL_DS; | |
169 | gdb_regs[GDB_PS] = 0; | |
170 | gdb_regs[GDB_CS] = __KERNEL_CS; | |
171 | gdb_regs[GDB_PC] = p->thread.ip; | |
172 | gdb_regs[GDB_SS] = __KERNEL_DS; | |
173 | gdb_regs[GDB_FS] = 0xFFFF; | |
174 | gdb_regs[GDB_GS] = 0xFFFF; | |
175 | #else | |
703a1edc JW |
176 | gdb_regs32[GDB_PS] = *(unsigned long *)(p->thread.sp + 8); |
177 | gdb_regs32[GDB_CS] = __KERNEL_CS; | |
178 | gdb_regs32[GDB_SS] = __KERNEL_DS; | |
0c23590f | 179 | gdb_regs[GDB_PC] = 0; |
82da3ff8 IM |
180 | gdb_regs[GDB_R8] = 0; |
181 | gdb_regs[GDB_R9] = 0; | |
182 | gdb_regs[GDB_R10] = 0; | |
183 | gdb_regs[GDB_R11] = 0; | |
184 | gdb_regs[GDB_R12] = 0; | |
185 | gdb_regs[GDB_R13] = 0; | |
186 | gdb_regs[GDB_R14] = 0; | |
187 | gdb_regs[GDB_R15] = 0; | |
188 | #endif | |
189 | gdb_regs[GDB_SP] = p->thread.sp; | |
190 | } | |
191 | ||
64e9ee30 JW |
192 | static struct hw_breakpoint { |
193 | unsigned enabled; | |
64e9ee30 | 194 | unsigned long addr; |
cc096749 JW |
195 | int len; |
196 | int type; | |
8c8aefce | 197 | struct perf_event * __percpu *pev; |
df493935 | 198 | } breakinfo[HBP_NUM]; |
64e9ee30 | 199 | |
031acd8c JW |
200 | static unsigned long early_dr7; |
201 | ||
64e9ee30 JW |
202 | static void kgdb_correct_hw_break(void) |
203 | { | |
64e9ee30 JW |
204 | int breakno; |
205 | ||
df493935 | 206 | for (breakno = 0; breakno < HBP_NUM; breakno++) { |
cc096749 JW |
207 | struct perf_event *bp; |
208 | struct arch_hw_breakpoint *info; | |
209 | int val; | |
210 | int cpu = raw_smp_processor_id(); | |
211 | if (!breakinfo[breakno].enabled) | |
212 | continue; | |
031acd8c JW |
213 | if (dbg_is_early) { |
214 | set_debugreg(breakinfo[breakno].addr, breakno); | |
215 | early_dr7 |= encode_dr7(breakno, | |
216 | breakinfo[breakno].len, | |
217 | breakinfo[breakno].type); | |
218 | set_debugreg(early_dr7, 7); | |
219 | continue; | |
220 | } | |
cc096749 JW |
221 | bp = *per_cpu_ptr(breakinfo[breakno].pev, cpu); |
222 | info = counter_arch_bp(bp); | |
223 | if (bp->attr.disabled != 1) | |
224 | continue; | |
225 | bp->attr.bp_addr = breakinfo[breakno].addr; | |
226 | bp->attr.bp_len = breakinfo[breakno].len; | |
227 | bp->attr.bp_type = breakinfo[breakno].type; | |
228 | info->address = breakinfo[breakno].addr; | |
229 | info->len = breakinfo[breakno].len; | |
230 | info->type = breakinfo[breakno].type; | |
231 | val = arch_install_hw_breakpoint(bp); | |
232 | if (!val) | |
233 | bp->attr.disabled = 0; | |
64e9ee30 | 234 | } |
031acd8c JW |
235 | if (!dbg_is_early) |
236 | hw_breakpoint_restore(); | |
64e9ee30 JW |
237 | } |
238 | ||
5352ae63 JW |
239 | static int hw_break_reserve_slot(int breakno) |
240 | { | |
241 | int cpu; | |
242 | int cnt = 0; | |
243 | struct perf_event **pevent; | |
244 | ||
031acd8c JW |
245 | if (dbg_is_early) |
246 | return 0; | |
247 | ||
5352ae63 JW |
248 | for_each_online_cpu(cpu) { |
249 | cnt++; | |
250 | pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu); | |
251 | if (dbg_reserve_bp_slot(*pevent)) | |
252 | goto fail; | |
253 | } | |
254 | ||
255 | return 0; | |
256 | ||
257 | fail: | |
258 | for_each_online_cpu(cpu) { | |
259 | cnt--; | |
260 | if (!cnt) | |
261 | break; | |
262 | pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu); | |
263 | dbg_release_bp_slot(*pevent); | |
264 | } | |
265 | return -1; | |
266 | } | |
267 | ||
268 | static int hw_break_release_slot(int breakno) | |
269 | { | |
270 | struct perf_event **pevent; | |
271 | int cpu; | |
272 | ||
031acd8c JW |
273 | if (dbg_is_early) |
274 | return 0; | |
275 | ||
5352ae63 JW |
276 | for_each_online_cpu(cpu) { |
277 | pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu); | |
278 | if (dbg_release_bp_slot(*pevent)) | |
279 | /* | |
280 | * The debugger is responisble for handing the retry on | |
281 | * remove failure. | |
282 | */ | |
283 | return -1; | |
284 | } | |
285 | return 0; | |
286 | } | |
287 | ||
64e9ee30 JW |
288 | static int |
289 | kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype) | |
290 | { | |
291 | int i; | |
292 | ||
df493935 | 293 | for (i = 0; i < HBP_NUM; i++) |
64e9ee30 JW |
294 | if (breakinfo[i].addr == addr && breakinfo[i].enabled) |
295 | break; | |
df493935 | 296 | if (i == HBP_NUM) |
64e9ee30 JW |
297 | return -1; |
298 | ||
5352ae63 JW |
299 | if (hw_break_release_slot(i)) { |
300 | printk(KERN_ERR "Cannot remove hw breakpoint at %lx\n", addr); | |
301 | return -1; | |
302 | } | |
64e9ee30 JW |
303 | breakinfo[i].enabled = 0; |
304 | ||
305 | return 0; | |
306 | } | |
307 | ||
308 | static void kgdb_remove_all_hw_break(void) | |
309 | { | |
310 | int i; | |
cc096749 JW |
311 | int cpu = raw_smp_processor_id(); |
312 | struct perf_event *bp; | |
64e9ee30 | 313 | |
df493935 | 314 | for (i = 0; i < HBP_NUM; i++) { |
cc096749 JW |
315 | if (!breakinfo[i].enabled) |
316 | continue; | |
317 | bp = *per_cpu_ptr(breakinfo[i].pev, cpu); | |
318 | if (bp->attr.disabled == 1) | |
319 | continue; | |
031acd8c JW |
320 | if (dbg_is_early) |
321 | early_dr7 &= ~encode_dr7(i, breakinfo[i].len, | |
322 | breakinfo[i].type); | |
323 | else | |
324 | arch_uninstall_hw_breakpoint(bp); | |
cc096749 JW |
325 | bp->attr.disabled = 1; |
326 | } | |
64e9ee30 JW |
327 | } |
328 | ||
329 | static int | |
330 | kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype) | |
331 | { | |
64e9ee30 JW |
332 | int i; |
333 | ||
df493935 | 334 | for (i = 0; i < HBP_NUM; i++) |
64e9ee30 JW |
335 | if (!breakinfo[i].enabled) |
336 | break; | |
df493935 | 337 | if (i == HBP_NUM) |
64e9ee30 JW |
338 | return -1; |
339 | ||
340 | switch (bptype) { | |
341 | case BP_HARDWARE_BREAKPOINT: | |
cc096749 JW |
342 | len = 1; |
343 | breakinfo[i].type = X86_BREAKPOINT_EXECUTE; | |
64e9ee30 JW |
344 | break; |
345 | case BP_WRITE_WATCHPOINT: | |
cc096749 | 346 | breakinfo[i].type = X86_BREAKPOINT_WRITE; |
64e9ee30 JW |
347 | break; |
348 | case BP_ACCESS_WATCHPOINT: | |
cc096749 | 349 | breakinfo[i].type = X86_BREAKPOINT_RW; |
64e9ee30 JW |
350 | break; |
351 | default: | |
352 | return -1; | |
353 | } | |
cc096749 JW |
354 | switch (len) { |
355 | case 1: | |
356 | breakinfo[i].len = X86_BREAKPOINT_LEN_1; | |
357 | break; | |
358 | case 2: | |
359 | breakinfo[i].len = X86_BREAKPOINT_LEN_2; | |
360 | break; | |
361 | case 4: | |
362 | breakinfo[i].len = X86_BREAKPOINT_LEN_4; | |
363 | break; | |
364 | #ifdef CONFIG_X86_64 | |
365 | case 8: | |
366 | breakinfo[i].len = X86_BREAKPOINT_LEN_8; | |
367 | break; | |
368 | #endif | |
369 | default: | |
64e9ee30 | 370 | return -1; |
cc096749 | 371 | } |
64e9ee30 | 372 | breakinfo[i].addr = addr; |
5352ae63 JW |
373 | if (hw_break_reserve_slot(i)) { |
374 | breakinfo[i].addr = 0; | |
375 | return -1; | |
376 | } | |
cc096749 | 377 | breakinfo[i].enabled = 1; |
64e9ee30 JW |
378 | |
379 | return 0; | |
380 | } | |
381 | ||
382 | /** | |
383 | * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb. | |
384 | * @regs: Current &struct pt_regs. | |
385 | * | |
386 | * This function will be called if the particular architecture must | |
387 | * disable hardware debugging while it is processing gdb packets or | |
388 | * handling exception. | |
389 | */ | |
390 | void kgdb_disable_hw_debug(struct pt_regs *regs) | |
391 | { | |
cc096749 JW |
392 | int i; |
393 | int cpu = raw_smp_processor_id(); | |
394 | struct perf_event *bp; | |
395 | ||
64e9ee30 JW |
396 | /* Disable hardware debugging while we are in kgdb: */ |
397 | set_debugreg(0UL, 7); | |
df493935 | 398 | for (i = 0; i < HBP_NUM; i++) { |
cc096749 JW |
399 | if (!breakinfo[i].enabled) |
400 | continue; | |
031acd8c JW |
401 | if (dbg_is_early) { |
402 | early_dr7 &= ~encode_dr7(i, breakinfo[i].len, | |
403 | breakinfo[i].type); | |
404 | continue; | |
405 | } | |
cc096749 JW |
406 | bp = *per_cpu_ptr(breakinfo[i].pev, cpu); |
407 | if (bp->attr.disabled == 1) | |
408 | continue; | |
409 | arch_uninstall_hw_breakpoint(bp); | |
410 | bp->attr.disabled = 1; | |
411 | } | |
64e9ee30 JW |
412 | } |
413 | ||
82da3ff8 IM |
414 | #ifdef CONFIG_SMP |
415 | /** | |
416 | * kgdb_roundup_cpus - Get other CPUs into a holding pattern | |
417 | * @flags: Current IRQ state | |
418 | * | |
419 | * On SMP systems, we need to get the attention of the other CPUs | |
420 | * and get them be in a known state. This should do what is needed | |
421 | * to get the other CPUs to call kgdb_wait(). Note that on some arches, | |
422 | * the NMI approach is not used for rounding up all the CPUs. For example, | |
423 | * in case of MIPS, smp_call_function() is used to roundup CPUs. In | |
424 | * this case, we have to make sure that interrupts are enabled before | |
425 | * calling smp_call_function(). The argument to this function is | |
426 | * the flags that will be used when restoring the interrupts. There is | |
427 | * local_irq_save() call before kgdb_roundup_cpus(). | |
428 | * | |
429 | * On non-SMP systems, this is not called. | |
430 | */ | |
431 | void kgdb_roundup_cpus(unsigned long flags) | |
432 | { | |
dac5f412 | 433 | apic->send_IPI_allbutself(APIC_DM_NMI); |
82da3ff8 IM |
434 | } |
435 | #endif | |
436 | ||
437 | /** | |
438 | * kgdb_arch_handle_exception - Handle architecture specific GDB packets. | |
439 | * @vector: The error vector of the exception that happened. | |
440 | * @signo: The signal number of the exception that happened. | |
441 | * @err_code: The error code of the exception that happened. | |
442 | * @remcom_in_buffer: The buffer of the packet we have read. | |
443 | * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into. | |
444 | * @regs: The &struct pt_regs of the current process. | |
445 | * | |
446 | * This function MUST handle the 'c' and 's' command packets, | |
447 | * as well packets to set / remove a hardware breakpoint, if used. | |
448 | * If there are additional packets which the hardware needs to handle, | |
449 | * they are handled here. The code should return -1 if it wants to | |
450 | * process more packets, and a %0 or %1 if it wants to exit from the | |
451 | * kgdb callback. | |
452 | */ | |
453 | int kgdb_arch_handle_exception(int e_vector, int signo, int err_code, | |
454 | char *remcomInBuffer, char *remcomOutBuffer, | |
455 | struct pt_regs *linux_regs) | |
456 | { | |
457 | unsigned long addr; | |
458 | char *ptr; | |
82da3ff8 IM |
459 | |
460 | switch (remcomInBuffer[0]) { | |
461 | case 'c': | |
462 | case 's': | |
463 | /* try to read optional parameter, pc unchanged if no parm */ | |
464 | ptr = &remcomInBuffer[1]; | |
465 | if (kgdb_hex2long(&ptr, &addr)) | |
466 | linux_regs->ip = addr; | |
737a460f JW |
467 | case 'D': |
468 | case 'k': | |
82da3ff8 | 469 | /* clear the trace bit */ |
fda31d7d | 470 | linux_regs->flags &= ~X86_EFLAGS_TF; |
82da3ff8 IM |
471 | atomic_set(&kgdb_cpu_doing_single_step, -1); |
472 | ||
473 | /* set the trace bit if we're stepping */ | |
474 | if (remcomInBuffer[0] == 's') { | |
fda31d7d | 475 | linux_regs->flags |= X86_EFLAGS_TF; |
d7161a65 JW |
476 | atomic_set(&kgdb_cpu_doing_single_step, |
477 | raw_smp_processor_id()); | |
82da3ff8 IM |
478 | } |
479 | ||
64e9ee30 JW |
480 | kgdb_correct_hw_break(); |
481 | ||
82da3ff8 IM |
482 | return 0; |
483 | } | |
484 | ||
485 | /* this means that we do not want to exit from the handler: */ | |
486 | return -1; | |
487 | } | |
488 | ||
489 | static inline int | |
490 | single_step_cont(struct pt_regs *regs, struct die_args *args) | |
491 | { | |
492 | /* | |
493 | * Single step exception from kernel space to user space so | |
494 | * eat the exception and continue the process: | |
495 | */ | |
496 | printk(KERN_ERR "KGDB: trap/step from kernel to user space, " | |
497 | "resuming...\n"); | |
498 | kgdb_arch_handle_exception(args->trapnr, args->signr, | |
499 | args->err, "c", "", regs); | |
62edab90 P |
500 | /* |
501 | * Reset the BS bit in dr6 (pointed by args->err) to | |
502 | * denote completion of processing | |
503 | */ | |
504 | (*(unsigned long *)ERR_PTR(args->err)) &= ~DR_STEP; | |
82da3ff8 IM |
505 | |
506 | return NOTIFY_STOP; | |
507 | } | |
508 | ||
d3597524 JW |
509 | static int was_in_debug_nmi[NR_CPUS]; |
510 | ||
82da3ff8 IM |
511 | static int __kgdb_notify(struct die_args *args, unsigned long cmd) |
512 | { | |
513 | struct pt_regs *regs = args->regs; | |
514 | ||
515 | switch (cmd) { | |
516 | case DIE_NMI: | |
517 | if (atomic_read(&kgdb_active) != -1) { | |
518 | /* KGDB CPU roundup */ | |
519 | kgdb_nmicallback(raw_smp_processor_id(), regs); | |
d3597524 JW |
520 | was_in_debug_nmi[raw_smp_processor_id()] = 1; |
521 | touch_nmi_watchdog(); | |
82da3ff8 IM |
522 | return NOTIFY_STOP; |
523 | } | |
524 | return NOTIFY_DONE; | |
525 | ||
526 | case DIE_NMI_IPI: | |
e85ceae9 | 527 | /* Just ignore, we will handle the roundup on DIE_NMI. */ |
d3597524 JW |
528 | return NOTIFY_DONE; |
529 | ||
530 | case DIE_NMIUNKNOWN: | |
531 | if (was_in_debug_nmi[raw_smp_processor_id()]) { | |
532 | was_in_debug_nmi[raw_smp_processor_id()] = 0; | |
82da3ff8 IM |
533 | return NOTIFY_STOP; |
534 | } | |
535 | return NOTIFY_DONE; | |
536 | ||
537 | case DIE_NMIWATCHDOG: | |
538 | if (atomic_read(&kgdb_active) != -1) { | |
539 | /* KGDB CPU roundup: */ | |
540 | kgdb_nmicallback(raw_smp_processor_id(), regs); | |
541 | return NOTIFY_STOP; | |
542 | } | |
543 | /* Enter debugger: */ | |
544 | break; | |
545 | ||
546 | case DIE_DEBUG: | |
cc096749 | 547 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1) { |
d7161a65 JW |
548 | if (user_mode(regs)) |
549 | return single_step_cont(regs, args); | |
550 | break; | |
551 | } else if (test_thread_flag(TIF_SINGLESTEP)) | |
552 | /* This means a user thread is single stepping | |
553 | * a system call which should be ignored | |
554 | */ | |
555 | return NOTIFY_DONE; | |
82da3ff8 IM |
556 | /* fall through */ |
557 | default: | |
558 | if (user_mode(regs)) | |
559 | return NOTIFY_DONE; | |
560 | } | |
561 | ||
f503b5ae | 562 | if (kgdb_handle_exception(args->trapnr, args->signr, cmd, regs)) |
82da3ff8 IM |
563 | return NOTIFY_DONE; |
564 | ||
737a460f JW |
565 | /* Must touch watchdog before return to normal operation */ |
566 | touch_nmi_watchdog(); | |
82da3ff8 IM |
567 | return NOTIFY_STOP; |
568 | } | |
569 | ||
f503b5ae JW |
570 | int kgdb_ll_trap(int cmd, const char *str, |
571 | struct pt_regs *regs, long err, int trap, int sig) | |
572 | { | |
573 | struct die_args args = { | |
574 | .regs = regs, | |
575 | .str = str, | |
576 | .err = err, | |
577 | .trapnr = trap, | |
578 | .signr = sig, | |
579 | ||
580 | }; | |
581 | ||
582 | if (!kgdb_io_module_registered) | |
583 | return NOTIFY_DONE; | |
584 | ||
585 | return __kgdb_notify(&args, cmd); | |
586 | } | |
f503b5ae | 587 | |
82da3ff8 IM |
588 | static int |
589 | kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr) | |
590 | { | |
591 | unsigned long flags; | |
592 | int ret; | |
593 | ||
594 | local_irq_save(flags); | |
595 | ret = __kgdb_notify(ptr, cmd); | |
596 | local_irq_restore(flags); | |
597 | ||
598 | return ret; | |
599 | } | |
600 | ||
601 | static struct notifier_block kgdb_notifier = { | |
602 | .notifier_call = kgdb_notify, | |
603 | ||
604 | /* | |
605 | * Lowest-prio notifier priority, we want to be notified last: | |
606 | */ | |
607 | .priority = -INT_MAX, | |
608 | }; | |
609 | ||
610 | /** | |
611 | * kgdb_arch_init - Perform any architecture specific initalization. | |
612 | * | |
613 | * This function will handle the initalization of any architecture | |
614 | * specific callbacks. | |
615 | */ | |
616 | int kgdb_arch_init(void) | |
0b4b3827 JW |
617 | { |
618 | return register_die_notifier(&kgdb_notifier); | |
619 | } | |
620 | ||
ba773f7c JW |
621 | static void kgdb_hw_overflow_handler(struct perf_event *event, int nmi, |
622 | struct perf_sample_data *data, struct pt_regs *regs) | |
623 | { | |
624 | kgdb_ll_trap(DIE_DEBUG, "debug", regs, 0, 0, SIGTRAP); | |
625 | } | |
626 | ||
0b4b3827 | 627 | void kgdb_arch_late(void) |
82da3ff8 | 628 | { |
cc096749 | 629 | int i, cpu; |
cc096749 JW |
630 | struct perf_event_attr attr; |
631 | struct perf_event **pevent; | |
632 | ||
cc096749 JW |
633 | /* |
634 | * Pre-allocate the hw breakpoint structions in the non-atomic | |
635 | * portion of kgdb because this operation requires mutexs to | |
636 | * complete. | |
637 | */ | |
ab310b5e | 638 | hw_breakpoint_init(&attr); |
cc096749 | 639 | attr.bp_addr = (unsigned long)kgdb_arch_init; |
cc096749 JW |
640 | attr.bp_len = HW_BREAKPOINT_LEN_1; |
641 | attr.bp_type = HW_BREAKPOINT_W; | |
642 | attr.disabled = 1; | |
df493935 | 643 | for (i = 0; i < HBP_NUM; i++) { |
0b4b3827 JW |
644 | if (breakinfo[i].pev) |
645 | continue; | |
cc096749 JW |
646 | breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL); |
647 | if (IS_ERR(breakinfo[i].pev)) { | |
0b4b3827 JW |
648 | printk(KERN_ERR "kgdb: Could not allocate hw" |
649 | "breakpoints\nDisabling the kernel debugger\n"); | |
cc096749 JW |
650 | breakinfo[i].pev = NULL; |
651 | kgdb_arch_exit(); | |
0b4b3827 | 652 | return; |
cc096749 JW |
653 | } |
654 | for_each_online_cpu(cpu) { | |
655 | pevent = per_cpu_ptr(breakinfo[i].pev, cpu); | |
656 | pevent[0]->hw.sample_period = 1; | |
ba773f7c | 657 | pevent[0]->overflow_handler = kgdb_hw_overflow_handler; |
cc096749 JW |
658 | if (pevent[0]->destroy != NULL) { |
659 | pevent[0]->destroy = NULL; | |
660 | release_bp_slot(*pevent); | |
661 | } | |
662 | } | |
663 | } | |
82da3ff8 IM |
664 | } |
665 | ||
666 | /** | |
667 | * kgdb_arch_exit - Perform any architecture specific uninitalization. | |
668 | * | |
669 | * This function will handle the uninitalization of any architecture | |
670 | * specific callbacks, for dynamic registration and unregistration. | |
671 | */ | |
672 | void kgdb_arch_exit(void) | |
673 | { | |
cc096749 JW |
674 | int i; |
675 | for (i = 0; i < 4; i++) { | |
676 | if (breakinfo[i].pev) { | |
677 | unregister_wide_hw_breakpoint(breakinfo[i].pev); | |
678 | breakinfo[i].pev = NULL; | |
679 | } | |
680 | } | |
82da3ff8 IM |
681 | unregister_die_notifier(&kgdb_notifier); |
682 | } | |
683 | ||
684 | /** | |
685 | * | |
686 | * kgdb_skipexception - Bail out of KGDB when we've been triggered. | |
687 | * @exception: Exception vector number | |
688 | * @regs: Current &struct pt_regs. | |
689 | * | |
690 | * On some architectures we need to skip a breakpoint exception when | |
691 | * it occurs after a breakpoint has been removed. | |
692 | * | |
693 | * Skip an int3 exception when it occurs after a breakpoint has been | |
694 | * removed. Backtrack eip by 1 since the int3 would have caused it to | |
695 | * increment by 1. | |
696 | */ | |
697 | int kgdb_skipexception(int exception, struct pt_regs *regs) | |
698 | { | |
699 | if (exception == 3 && kgdb_isremovedbreak(regs->ip - 1)) { | |
700 | regs->ip -= 1; | |
701 | return 1; | |
702 | } | |
703 | return 0; | |
704 | } | |
705 | ||
706 | unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs) | |
707 | { | |
708 | if (exception == 3) | |
709 | return instruction_pointer(regs) - 1; | |
710 | return instruction_pointer(regs); | |
711 | } | |
712 | ||
dcc78711 JW |
713 | void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip) |
714 | { | |
715 | regs->ip = ip; | |
716 | } | |
717 | ||
82da3ff8 IM |
718 | struct kgdb_arch arch_kgdb_ops = { |
719 | /* Breakpoint instruction: */ | |
720 | .gdb_bpt_instr = { 0xcc }, | |
64e9ee30 JW |
721 | .flags = KGDB_HW_BREAKPOINT, |
722 | .set_hw_breakpoint = kgdb_set_hw_break, | |
723 | .remove_hw_breakpoint = kgdb_remove_hw_break, | |
724 | .remove_all_hw_break = kgdb_remove_all_hw_break, | |
725 | .correct_hw_break = kgdb_correct_hw_break, | |
82da3ff8 | 726 | }; |